3,275 research outputs found

    Strong decays of DˉK\bar{D}^{*}K^{*} molecules and the newly observed X0,1X_{0,1} states

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    Lately, the LHCb Collaboration reported the discovery of two new states in the B+D+DK+B^+\rightarrow D^+D^- K^+ decay, i.e., X0(2866)X_0(2866) and X1(2904)X_1(2904). In the present work, we study whether these states can be understood as DKˉD^*\bar{K}^* molecules from the perspective of their two-body strong decays into DK+D^-K^+ via triangle diagrams and three-body decays into DKˉπD^*\bar{K}\pi. The coupling of the two states to DKˉD^*\bar{K}^* are determined from the Weinberg compositeness condition, while the other relevant couplings are well known. The obtained strong decay width for the X0(2866)X_0(2866), in marginal agreement with the experimental value within the uncertainty of the model, hints at a large DKˉD^*\bar{K}^* component in its wave function. On the other hand, the strong decay width for the X1(2904)X_1(2904), much smaller than its experimental counterpart, effectively rules out its assignment as a DKˉD^*\bar{K}^* molecule.Comment: 5 pages, 2 figure

    Representation Disparity-aware Distillation for 3D Object Detection

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    In this paper, we focus on developing knowledge distillation (KD) for compact 3D detectors. We observe that off-the-shelf KD methods manifest their efficacy only when the teacher model and student counterpart share similar intermediate feature representations. This might explain why they are less effective in building extreme-compact 3D detectors where significant representation disparity arises due primarily to the intrinsic sparsity and irregularity in 3D point clouds. This paper presents a novel representation disparity-aware distillation (RDD) method to address the representation disparity issue and reduce performance gap between compact students and over-parameterized teachers. This is accomplished by building our RDD from an innovative perspective of information bottleneck (IB), which can effectively minimize the disparity of proposal region pairs from student and teacher in features and logits. Extensive experiments are performed to demonstrate the superiority of our RDD over existing KD methods. For example, our RDD increases mAP of CP-Voxel-S to 57.1% on nuScenes dataset, which even surpasses teacher performance while taking up only 42% FLOPs.Comment: Accepted by ICCV2023. arXiv admin note: text overlap with arXiv:2205.15156 by other author

    Effectiveness of laparoscopic sleeve gastrectomy for weight loss and obesity-associated co-morbidities: a 3-year outcome from Mainland Chinese patients

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    AbstractBackgroundLaparoscopic sleeve gastrectomy (LSG) is becoming a stand-alone bariatric surgery for obesity, but its effectiveness for Mainland Chinese patients remains unclear.ObjectivesTo evaluate the effectiveness and safety of LSG for Mainland Chinese patientsSettingA tertiary hospitalMethodsRetrospective analysis of patients admitted for LSG between January 2011 and February 2012 was performed. Medium-term outcome measures were: total weight loss (%TWL), excess weight loss (%EWL), co-morbidities, improvement, and complications.ResultsSeventy patients (body mass index [BMI] 40.8±5.9 kg/m2) underwent LSG, comprising 40 women and 30 men. The most common co-morbidity was diabetes (n = 29, 41.4%). Lost to follow-up rate for weight loss was 15.7%, 31.4%, and 41% at 1, 2, and 3 years. The %TWL was 34.4±6.1, 34.7±6.2 and 33.7±7.1 at 1, 2, and 3 years. The %EWL increased to 77.1±13.0, 77.9±12.2 and 77.2±13.1 at 1, 2, and 3years. The proportions of patients having successful weight loss were 100% or 85% at 3 years according the definition of %TWL>10% or %EWL>50%. Approximately 79.3%, 51.7%, and 44.8% of patients completed follow-up for glycemic control at each time point, respectively. The proportions of patients with optimal glycemic control (fasting blood glucose [FBG]<5.6 mmol/L; hemoglobin A1C [HbA1C]<6.5%) were 47.9%, 60.0%, and 69.2% at 1, 2, and 3years. The weight loss and glycemic control effect may be greater in the high BMI group (≥40 kg/m2). Early and late complications occurred in 8.6% and 7.1% of patients during follow-up.ConclusionsLSG is effective in weight loss and glycemic control and is safe for Mainland Chinese obese patients, especially for patients with a BMI≥40 kg/m2

    Sex‐specific activation of SK current by isoproterenol facilitates action potential triangulation and arrhythmogenesis in rabbit ventricles

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    Sex has a large influence on cardiac electrophysiological properties. Whether sex differences exist in apamin‐sensitive small conductance Ca2+‐activated K+ (SK) current (IKAS) remains unknown. We performed optical mapping, transmembrane potential, patch clamp, western blot and immunostaining in 62 normal rabbit ventricles, including 32 females and 30 males. IKAS blockade by apamin only minimally prolonged action potential (AP) duration (APD) in the basal condition for both sexes, but significantly prolonged APD in the presence of isoproterenol in females. Apamin prolonged APD at the level of 25% repolarization (APD25) more prominently than APD at the level of 80% repolarization (APD80), consequently reversing isoproterenol‐induced AP triangulation in females. In comparison, apamin prolonged APD to a significantly lesser extent in males and failed to restore the AP plateau during isoproterenol infusion. IKAS in males did not respond to the L‐type calcium current agonist BayK8644, but was amplified by the casein kinase 2 (CK2) inhibitor 4,5,6,7‐tetrabromobenzotriazole. In addition, whole‐cell outward IKAS densities in ventricular cardiomyocytes were significantly larger in females than in males. SK channel subtype 2 (SK2) protein expression was higher and the CK2/SK2 ratio was lower in females than in males. IKAS activation in females induced negative intracellular Ca2+–voltage coupling, promoted electromechanically discordant phase 2 repolarization alternans and facilitated ventricular fibrillation (VF). Apamin eliminated the negative Ca2+–voltage coupling, attenuated alternans and reduced VF inducibility, phase singularities and dominant frequencies in females, but not in males. We conclude that β‐adrenergic stimulation activates ventricular IKAS in females to a much greater extent than in males. IKAS activation plays an important role in ventricular arrhythmogenesis in females during sympathetic stimulation

    Leakage Characteristic of Helical Groove Seal Designed in Reactor Coolant Pump

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    Helical groove seal is designed in reactor coolant pump to control the leakage along the front surface of the impeller face due to its higher resistance than the circumferentially grooved seal. The flow and the friction factors in helical groove seals are predicted by employing a commercial CFD code, FLUENT. The friction factors of the helical groove seals with helix angles varying from 20 deg to 50 deg, at a range of rotational speed and axial Reynolds number, were, respectively, calculated. For the helically grooved stator with the helix angle greater than 20 deg, the leakage shows an upward trend with the helix angle. The circumferentially grooved stator has a lower resistance to leakage than the 20 deg and 30 deg stators. It can be predicated that, for a bigger helix angle, the friction factor increases slightly with an increase in high axial Reynolds number, which arises from the high-pressure operation condition, and the friction factor is generally sensitive to changes in the helix angle in this operation condition. The study lays the theoretical foundation for liquid seal design of reactor coolant pump and future experimental study to account for the high-pressure condition affecting the leakage characteristic

    Formation Flight in Dense Environments

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    Formation flight has a vast potential for aerial robot swarms in various applications. However, existing methods lack the capability to achieve fully autonomous large-scale formation flight in dense environments. To bridge the gap, we present a complete formation flight system that effectively integrates real-world constraints into aerial formation navigation. This paper proposes a differentiable graph-based metric to quantify the overall similarity error between formations. This metric is invariant to rotation, translation, and scaling, providing more freedom for formation coordination. We design a distributed trajectory optimization framework that considers formation similarity, obstacle avoidance, and dynamic feasibility. The optimization is decoupled to make large-scale formation flights computationally feasible. To improve the elasticity of formation navigation in highly constrained scenes, we present a swarm reorganization method which adaptively adjusts the formation parameters and task assignments by generating local navigation goals. A novel swarm agreement strategy called global-remap-local-replan and a formation-level path planner is proposed in this work to coordinate the swarm global planning and local trajectory optimizations efficiently. To validate the proposed method, we design comprehensive benchmarks and simulations with other cutting-edge works in terms of adaptability, predictability, elasticity, resilience, and efficiency. Finally, integrated with palm-sized swarm platforms with onboard computers and sensors, the proposed method demonstrates its efficiency and robustness by achieving the largest scale formation flight in dense outdoor environments.Comment: Submitted for IEEE Transactions on Robotic
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